How to do same as 'nmap' command from within a D program?

[Daren Scot Wilson]

On Sunday, 23 January 2022 at 06:30:11 UTC, frame wrote:
> On Saturday, 22 January 2022 at 20:55:38 UTC, Daren Scot Wilson 
> wrote:
>
>> I don't see any D std.* libraries that do this. Are there a 
>> Dub packages I should look at?
>
> If you really want to this in D without any external app or OS 
> API you could just ping all possible hosts, see which respond 
> and then use `getHostByAddr()` to find the hostname.
>
> Another more professional way is to query the ARP protocol, 
> where you send a packet as broadcast to all interfaces in the 
> network to find a MAC for a given IP - if any host responses 
> with a MAC, the host is up.
>
> You have to build the packet data for yourself, there are 
> examples on the web. The socket to use is family:INET, type:RAW 
> and protocol:ICMP for ping or RAW for ARP or anything that 
> isn't listed in D.
>
> As you can see, it's required to test every possible IP out 
> (except for any other discovery protocols supported by your 
> network/router). For this reason, any OS does this scan 
> periodically and caches the result. On UNIX you can just 
> directly read the file `/proc/net/arp`, no need to use nmap.



I'll try this. Looks more educational.  This is a personal 
project, a show-off project. Once I'm done with another portion 
of it, I'll get onto this. My program will need to scan only 
once, not even once per run, since I can stash the results in a 
config file, but once whenever the user knows the hardware 
devices have changed.